Hydraulic cylinder-zero external volumetric change type



Dec. 21, 1965 z. B. ANDREWS 3,

HYDRAULIC CYLINDER-ZERO EXTERNAL VOLUMETRIC CHANGE TYPE 2 Sheets-Sheet 1Filed May 15, 1964 INVENTOR. ZENAS B. ANDREWS MLM,

AT TORNEY z. B. ANDREWS 3,224,751 HYDRAULIC CYLINDER-ZERO EXTERNALVOLUMETRIC CHANGE TYPE Dec 21, 1965 2 Sheets-Sheet 2 Filed May J5, 1964IN VENTOR.

ZENAS B. ANDREWS urlfIIf/lfllfWfW/llllll' muw ATTORNEY United StatesPatent 3,224,751 HYDRAULIC CYLINDER-ZERO EXTERNAL VOLUMETRIC CHANGE TYPEZenas B. Andrews, Los Altos, Califl, assignor, by mesne assignments, tothe United States of America as represented by the Secretary of the NavyFiled May 15, 1964, Ser. No. 368,450 2 Claims. (Cl. 2671) This inventionrelates to missile launchers and particularly to mountings for suchdevices.

In launching certain missiles from a ships deck or a submergedsubmarine, a launcher is utilized that employs a vertically disposedfiring tube. For various reasons, the launcher is a single capacity unitand is used in batteries.

The firing tube of each launcher is supported within an outer tube orhousing which is secured to the vessels structure. To isolate shock, ashock absorbing device is fixed between the firing tube and its housing.This is normally a resilient member, like a spring.

A properly supported firing tube requires that the support hold thefiring tube rigidly, or in a locked position, while the missile is beingejected, but that the locked position be instantly broken if motion isimparted to the firing tube by an external explosion.

In the invention, the firing tube is separated from the outer tube byelastomeric mountings to absorb and prevent jars and strains from beingtransmitted between the firing tube and the housing. A strut is alsomounted between the firing and outer tubes which is a hydraulic memberhaving piston-like compression and tension valves. The strut is normallylocked out, that is, the valves are separated under the fluid pressurewithin the strut. An external force of a predetermined magnitude resultsin stroking of the compression or tension valve. Movement of a valvedisplaces fluid from the cylinder and opens a passageway into a lowpressure chamber. The locked position of the strut is immediatelybroken, and removes its resistance to the normal action of theelastomeric mounting.

The strut is self-centering in that the pressure within it causes bothpiston valves to move into the locked position. The action of the pistonvalves does not cause fluid flow in the lines connecting the strut.Provision is made in the form of an accumulator to receive fluiddisplaced at an extremely rapid rate from the strut. One accumulator iscapable of serving both piston valves, or a separate accumulator may beprovided for each of them. The seals are disposed so that leakage isfrom a high pressure area to a low pressure area within the strut, andany external leakage from the strut is from a low pressure area. Theconstruction of the accumulator is such that excessive forces within thestrut only cause destruction of one of its replaceable elements.

Various other features and advantages of the invention will becomeapparent upon reading the detailed description in view of the drawingwherein:

FIG. 1 is a sectional view of a portion of a submarine equipped withlaunchers employing the invention showing a launcher in side elevationand a sectional view of another;

FIG. 2 is a longitudinal sectional view, with some parts broken away, ofone of the struts showing it in its locked position;

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FIG. 3 is similar to FIG. 2 but shows the position of the piston valvesduring a compression stroke;

FIG. 4 is like FIG. 2 but with the piston valves under a tension stroke;and

FIG. 5 is a sectional view of the accumulator along the line 55 of FIG.4.

Referring to the drawing, in FIG. 1, 10 indicates a portion of a vessel,such as a submarine, provided with a number of single capacity missilelaunchers. Each launcher, 12, generally includes a firing tube 14, whichcarries a missile 1, disposed in an outer tube 16, and a source ofpressurized fluid as the flask 18. The flask 18 is connected to thefiring tube 14 through a launcher valve, not shown. Opening the valvereleases the pres surized fluid beneath the missile 1 and ejects it fromthe launcher.

The outer tube 16 is sunk into the hull of the craft 10 and disposed insubstantially a vertical position with its upper end terminating at thedeck level. It is secured to the crafts structure by welds, struts, orsome other well known means, not shown.

The inner or firing tube 14 is concentrically mounted within the outertube 16 on resilient members, such as the rubber rings shown, at 19.

To hold the firing tube 14 rigidly while firing a missile against normalmovements and forces, there are a plurality of struts 20, 21, 20' and21. Preferably there are four, only two shown, equally spaced struts ina plane near the top of the firing tube and four more similarly spacedin a lower plane. As shown in FIG. 1, movement of the firing tube 14 tothe left will subject strut 20 to a compression force while its opposedmember 21 undergoes a tension force. Movement to the right reverses theforces applied to the struts.

Each strut, for instance strut 20 in FIG. 4, has a tubular casing 22recessed in one end portion to provide a cylindrically shaped, highpressure chamber 24 with an aperture 25 through its end wall that formsa cylinder for guiding a piston-like, compression stroke valve 40. Theother end portion is bored through to form a cylinder 26 for guiding atension stroke valve 42. The tension cylinder 26 is closed at its farend by a cap 28 which is joined to it by a threaded sleeve 30. An eye 32in cap 28 is designed for securing the strut to a lug or bracket 33,fixed to either the firing or outer tubes.

A central port 34 is provided in the casing 22 intermediate its ends forfilling the high pressure chamber 24 with pressurized hydraulic fluid,and a port 36 near the end wall 38 for returning the fluid. The ports 36and 38 are coupled by lines having check valves to a source of fluidpressure and a return tank, not shown.

Since both the compression valve 40 and the tension valve 42 are similarin construction, like parts are indicated with the same referencecharacters, except they are primed for the tension stroke valve 42 andonly the compression stroke valve will be described. It has a head, 44,of slightly smaller size than the high pressure chamber 24 in which itis disposed so that there is a space, 46, between the two for passage offluid from one side of the head to the other, and a tubular stem, 48,with a bore 49. A hole in the center of the valve head, 44, is alignedwith the stem bore 49; it is smaller than the bore, 49, and as a result,there is a shoulder 52 within it.

The valves, 40 and 42, are positioned within the high pressure chamberwith their heads opposed. The stem 48 of the compression valve 40 ismounted in and extends through the aperture or cylinder 25, and the stem48' of the tension valve 42 extends into the bore or tension cylinder26. The stems, 48 and 48, have sufficient length to permit movement ofthe valves in the high pressure chamber 24 without being dismounted fromtheir cylinders, 25 and 26.

The annular under surfaces, 54 and 54', of the compression and tensionvalves, 40 and 42, respectively seat on the ends of the high pressurechamber 24 on high pressure sealing rings, 56 and 56'.

A connecting rod 60 having an eye 62 at one end for attachment to abracket, as shown at 64, secured to either the firing tube 14 or theouter tube 16, has its other end inserted through the bore of thecompression valves stem 48 and into the bore of the tension valve stem48. When the valves, 40 and 42, are seated or in the locked position, asin FIG. 2, the inserted end of the piston rod 60 terminate-s a shortdistance within the tension valves stem 48. The size of the rod portionsdisposed within the bore of valve stems, 48 and 48, are dimensioned fora sliding fit. As shown in FIGS. 24, the intermediate portion 62 of thepiston rod 60, as defined by the distance between the valves (40 and 42)when seated is sized for a sliding fit within the holes, 50 and 50', ofthe valve heads. This construction permits movement between the valvesand the rod and forms shoulders, 64 and 66, on the rod portion withinthe valve stems which are adapted and engage and disengage with theshoulders 52 and 52 within the valve stem.

Movement between the valves and the rod 60 also produces a low pressurefluid chamber between the shoulders on the rod 60 and the under surfaceof the piston heads. Thus, movement of the compression valve 40, as inFIG. 3, creates chamber 68 in tension valve stem 48', and movement ofthe tension valve 42, as in FIG. 4, creates a chamber 70 in thecompression valve stem 48.

Movement of a piston, 40 or 42, permits fluid flow between the highpressure chamber 24 and a low pressure chamber, 68 or 70. For thispurpose, the intermediate portion 62 of the rod 60 is provided with alongitudinal passage 72 which is connected by radial passages 74 and 75to longitudinal grooves, as shown at 76 and 78, that penetrate theshoulders 64 and 66 in a direction toward the piston head. The endsurfaces defining the high pressure chamber 24 are also provided withannular grooves, 80 and 82, around the cylinders, 25 and 26, whichreceive the valve stems and the walls of the stems are penetrated withapertures, 84 and 86, at the neck between the stem and head of thevalves.

In the operation of the device, the high pressure chamber 24 is filledwith pressurized fluid which separates the valves 40 and 42 causing themto seat as in FIG. 2. When a compression force is applied to the strut(FIG. 3), the rod 60 moves inwardly carrying with it compression valve40 off its seat, since the rods shoulder 64 is engaged with the valveshoulder 52. At the other end, the rod shoulder 66 disengages from thevalve shoulder 54' in the tension valve stem 48'. Part of the stem 48 ofthe valve 40 enters the high pressure chamber, decreasing its fluidvolume. Fluid flows around the compression valve head through the space46, through the stem aperture 84 into passage 72 in the rod 60 andempties in chamber 68 under the head of the tension valve 42, which isincreasing in volume.

With a tension force applied to the strut 20 (FIG. 4), rod 60 andtension valve 42 are engaged by shoulders 66 and 52 and valve 42 isunseated; whereas, shoulders 64 and 52 are disengaged and chamber 70 inthe compression valve stem 48 increases in volume. Flow then is aroundthe head of valve 42 through its stem aperture 86, the longitudinalpassage 72 of rod 60 and into the chamber 70.

When external forces are removed, the cylinder is selfcentered in thatthe liquid pressure in the high pressure chamber 24 causes both thecompression and tension piston, 40 and 42, to move to the locked outposition, FIG. 2.

Four high pressure seals, 56, 56', 88 and 88' and four low pressureseals, 90, 90', 92 and 92' are provided as shown. With this design, anyleakage in the high pressure seal will result in leakage into lowpressure chambers. External dynamic seal liquid leakage can only occuracross the low pressure seals.

To provide for a rapid displacement of fluid within the high pressurechamber 24, that is when the low pressure chambers, 70 and 72, withinthe stems of the valves 40 and 42, are incapable of handling thedisplaced fluid, a passageway 94 is provided which connects the annulargroove 82 with an accumulator 96. The latter comprises an annularprojection 97 on the outer surface of the casing 22 which is threadedlyclosed with a clip 98. A diaphragm 99 is secured at its periphery by thecap 88 over the passageway 94. The diaphragm is stiffened at its centerby a disk 100 and urged down toward the passageway 94 by a spring 102. Aprojection 104 from the disk 100 extends into a tubular member 106 onthe under side of the cap for guiding vertical movement of thediaphragm. Fluid pressure enters the passageway 94, and if of sufficientforce, will drive the diaphragm 99 upward and fill the space developedunder it. If this proves insufficient, a groove 108 is furnished aroundthe exterior of cap 98 which will permit the cap to fracture and allowfluid to escape.

Obviously a similar accumulator may be provided for opposite side of thehigh pressure chamber 24 as well as various other changes andarrangements of parts without departing from the spirit and scope of theinvention, the form hereinbefore described being merely a preferredembodiment thereof.

What is claimed:

1. A hydraulic strut for use between two relatively movable structurescomprising a casing adapted to be secured to one of said structures andhaving a high pressure fluid chamber therein connected by an aperturethrough one end of said casing defining a compression cylinder and abore in the other end defining a tension cylinder;

a compression stroke valve including a head disposed in said highpressure chamber having a hollow stern extending through saidcompression cylinder;

a tension stroke valve including a head disposed in said high pressurechamber and a hollow stem extending in said tension cylinder;

said heads of said compression and tension stroke valves each having ahole aligned with the hollow of its stem;

a rod having an end adapted to be secured to the other said structureand the other end inserted through the hollow of said stem of saidcompression stroke valve and into the hollow of said stem of saidtension stroke valve;

a shoulder on the portion of said rod within the hollow of said tensionstroke valve stem and a shoulder on the portion of said rod within thehollow of said compression stroke valve stem adapted to engage the underside of said head within their stems whereby inward movement of said rodunseats said compression stroke valve moving the stern thereof into saidhigh pressure chamber, displacing fluid and creating a low pressurecavity between the rod shoulder and valve head in said compression valvestem, and outward movement of said rod unseats said tension stroke Valvemoving its stern into said high pressure chamber and creates a lowpressure cavity between the rod shoulder and valve head in saidcompression valve stem;

and passage means connecting said high pressure chamber of the hollowsof said stems of said valves including a groove in the end Wall aroundsaid aperture and said bore, a hole in the stem of said valves at theneck thereof and a passage through the intermediate portion of said rod,and said valve heads adapted to close and open said passage means withseating and unseating thereof over said groove.

2. The device of claim 1 including an accumulator References Cited bythe Examiner UNITED STATES PATENTS Zumwalt 267-64 X Smith 267-64 XSiegel et al 89-1.7 Smith 26764 Andrews 2671 May 188100X connected tosaid passage means having a normally closed 10 BENJAMIN BORCHELT PrmmryExa'mner' SAMUEL W. ENGLE, Examiner.

spring diaphragm.

1. A HYDRAULIC STRUT FOR USE BETWEEN TWO RELATIVELY MOVABLE STRUCTURESCOMPRISING A CASING ADAPTED TO BE SECURED TO ONE OF SAID STRUCTURES ANDHAVING A HIGH PRESSURE FLUID CHAMBER THEREIN CONNECTED BY AN APERTURETHROUGH ONE END OF SAID CASING DEFINING A COMPRESSION CYLINDER AND ABORE IN THE OTHER END DEFINING A TENSION CYLINDER; A COMPRESSION STROKEVALVE INCLUDING A HEAD DISPOSED IN SAID HIGH PRESSURE CHAMBER HAVING AHOLLOW STEM EXTENDING THROUGH SAID COMPRESSION CYLINDER; A TENSIONSTROKE VALVE INCLUDING A HEAD DISPOSED IN SAID HIGH PRESSURE CHAMBER ANDA HOLLOW STEM EXTENDING IN SAID TENSION CYLINDER; SAID HEADS OF SAIDCOMPRESSION AND TENSION STROKE VALVES EACH HAVING A HOLE ALIGNED WITHTHE HOLLOW OF ITS STEM; A ROD HAVING AN END ADAPTED TO BE SECURED TO THEOTHER SAID STRUCTURE AND THE OTHER END INSERTED THROUGH THE HOLLOW OFSAID STEM OF SAID COMPRESSION STROKE VALVE AND INTO THE HOLLOW OF SAIDSTEM OF SAID TENSION STROKE VALVE; A SHOULDER ON THE PORTION OF SAID RODWITHIN THE HOLLOW OF SAID TENSION STROKE VALVE STEM AND A SHOULDER ONTHE PORTION OF SAID ROD WITHIN THE HOLLOW OF SAID COMPRESSION STROKEVALVE STEM ADAPTED TO ENGAGE THE UNDER SIDE OF SAID HEAD WITHIN THEIRSTEMS WHEREBY INWARD MOVEMENT OF SAID ROD UNSEATS AND COMPRESSION STROKEVALVE MOVING THE STEM THEREOF INTO SAID HIGH PRSSURE CHAMBER, DISPLACINGFLUID AND CREATING A LOW PRESSURE CAVITY BETWEEN THE ROD SHOULDER ANDVALVE HEAD IN SAID COMPRESSION VALVE STEM, AND OUTWARD MOVEMENT OF SAIDROD UNSEATS SAID TENSION STROKE VALVE MOVING ITS STEM INTO SAID HIGHPRESSURE CHAMBER AND CREATE A LOW PRESSURE CAVITY BETWEEN THE RODSHOULDER AND VALVE HEAD IN SAID COMPRESSION VALVE STEM; AND PASSAGEMEANS CONNECTING SAID HIGH PRESSURE CHAMBER OF THE HOLLOWS OF SAID STEMSOF SAID VALVE INCLUDING A GROOVE IN THE END WALL AROUND SAID APERTUREAND SAID BORE, A HOLE IN THE STEM OF SAID VALVES AT THE NECK THEREOF ANDA PASSAGE THROUGH THE INTERMEDIATE PORTION OF SAID ROD, AND SAID VALVEHEADS ADAPTED TO CLOSE AND OPEN SAID PASSAGE MEANS WITH SEATING ANDUNSEATING THEREOF OVER SAID GROOVE.